Electric motor



(No Model.) 2 Sheets-Sheet l; H. B. SLATER. ELECTRIC MOTOR.

No. 404,661. Patented June 4, 1889 KFZT/AESE 1.7V VENTOR a %M 6446; .Z%4/% 'Wwzz .dt orney (No Model.) 2 Sheets-Sheet 2. H. B. SLATER.

ELECTRIC MOTOR.

No. 404,661. Patented June 4, 1889.

UNITED STATES PATENT OFFICE.

HENRY B. SLATER, OF DETROIT, MICHIGAN, ASSIGNOR TO THE BELDING MOTOR AND MANUFACTURING COMPANY, OF CHICAGO, ILLINOIS.

ELECTRIC MOTOR.

SPECIFICATION forming part of Letters Patent No. 404,661, dated June 4, 1889.

Application filed December 15, 1887. Serial No. 258,007. (No model.)

To all whom, it may concern:

Beitknown thatl, HENRY I3. SLATER, a citizen of the United States, residing at Detroit, county of \Vayne, State of Michigan, have invented a certain new and useful Improvement in Electric Motors; and I declare the following to be a full, clear, and exact description of the same, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specification.

My invention consists of the combinations hereinafter specified, and defined with greater particularity in the claims.

In the drawings, Figure l is a side elevation of a device embodying my invention mounted upon a bracket. Fig. 2 is an end elevation of the same removed from the bracket. Fig. 3 is a plan view. Figs. 4 and 5 are separate views illustrating how the brush-holder is retained in any one of several positions of adjustment. Fig. 6 illustrates how the armature may be made up of laminated sections. Fig. 7 illustrates the means of attaching a flexible shaft to the shaft of the machine. Fig. 8 is an enlarged cross-section of the shaft.

My invention has for its object the production of a motor which is specially adapted for dentists use and for similar light work. It embodies, however, features which are equally applicable in all dynamo-machines, whether generators or motors, and in that respect I would have it understood that it embraces all such constructions regardless of their size and regardless of the purpose for which they are employed.

In carrying out my invention, A represents the field-magnets, of which there are four, two upon each side of the shaft and arranged upon opposite sides of the armature -ring. These magnets all stand out at right angles with the shaft. They terminate at their upper ends in a common pole-piece D, which is carried overand caused to closely embrace the surface of the armature-ring. That portion which projects over the armature-ring is made of substantially uniform thickness, so

as to bring its pole or intensely-excited sec tion in close proximity to the bobbins on the armature. The lower pole-piece has projectin g from it a vertical pivot O, which is adapted to enter a collar 0 on a bracket or any convenient support. This permits the machine to stand always in a vertical position, yet to swivel about its axis as a center, thus enabling the operator to apply his power in any direction without any inconvenience.

D is the lnush-holder. It is swivelcd about the collaizE, to which it is held by a nut E and a bolt or screw E. This brush-holder E has a series of shallmvcavities e on its inner face, and a spring pawl or detent e in the frame is adapted to spring in and out of these cavities e as the brush-holder is rotated. This gives to the holder sufficient friction at these various points to hold it with comparative rigidity and not permit it to yield except by the deliberate will of the operator. In this way the operator may adjust his brushes so as to give his machine any desired speed. Should he desire to vary the speed, he may raise or lower the lever slightly with his hand, causing the detent e to ride into the next cavity 6, and by bringing the lever into the proper position may entirely neutralize the effect of the current 011 the armature and cause the machine to stop. This yielding friction is a matter of great convenience with dentists and others who must act quickly without time for the exercise of particular care in leaving the brushes at the proper positions.

F is a shaft. It is cored out, as shown in Fig. 7, for the insertion of the plug F, which constitutes the extremity of the flexible shaft W. A coupling F is employed for connecting the tube with the frame of the machine.

A screw f is caused to enter through the shaft I into alongitudinal groove f in the plug F. lhls causes the flexible shaft to revolve with the shaft of the armature.

In Fig. 6 is shown my improved armaturering. It is composed of sections G G, each of which is a segment of the ring. These segments are engaged at their extremities, so that when slid together they cannot uncouple.

The object is to permit the armature to'be wound with its bobbins prior to coupling the segments. Then the segments are engaged with each other, as shown, and the armature completed by windingbobbins over the joints. This armature-ring may be made solid; but

' I prefer to make it of laminated sections, as

shown at the bottom in Fig. 6that is to say, it is made up of sheets of metal placed side by side, as shown at g.

I prefer generally to wind the bobbins on a mandrel and then slip them upon the sections of the armature-ring, and, finally, when thus provided with bobbins to engage the armature series of hollow cavities e and a spring pawl or detent e for giving to it a substantially rigid engagement at each of a series of adjustments, said spring-detent and cavities being housed between the face of the brushholder and the adjacent supporting part of the frame, substantially as and for the purposes described.

2. An armature-ring made in sections, having a dovetail tenon and groove, whereby said sections are adapted to be slipped together and engaged at their extremities, each said section composed of laminae g, substantially as and for the purpose described.

In testimony whereof I sign this specification in the presence of two witnesses.

HENRY B. SLATER. 

